Linux Januar 2012/Add users

Purpose

When adding students on a Linux/UNIX box its desirable to let the students choice their own login names.

How to add student logins

Make a username and password public to the students. When the students login they are prompted for desired loginname/password

Adding the create-students account

Add user ny with password ny or whatever username/password you prefer to make public to the students. remember to change all references in the following to the username you choice.

File: /home/ny/.profile

Add the following line to the start of /home/ny/.profile

trap '' 1 2 3 15

Add the following two lines to the end of /home/ny/.profile

/home/ny/bin/nybruger
exit

File: /etc/sudoers

Add the following line to /etc/sudoers using visudo

ny ALL = NOPASSWD: /usr/sbin/adduser [a-zA-Z0-9]*

File: /home/ny/bin/nybruger

Create the /home/ny/bin directory and add the file /home/ny/bin/nybruger with the following content. (Remember to change mode to executable)

#!/bin/bash
tput clear
echo -e "                        Tilføj bruger"
echo -e "                        ============="
echo -e "\n\n\nIndtast dit ønskede bruger login. Et ord indeholdene bogstaver eller/og tal."
echo -en "\nBruger login: "
read LOGIN
sudo /usr/sbin/adduser $LOGIN
if grep $LOGIN /etc/passwd
then
  COUNT=5
  while test "$COUNT" -gt 0
  do
    echo -en "\r Bruger $LOGIN oprettet. Sessionen afsluttes om $COUNT sekunder"
    let COUNT=COUNT-1
    sleep 1
  done
else
COUNT=5
  while test "$COUNT" -gt 0
  do
    echo -en "\r FEJL: Bruger $LOGIN er IKKE oprettet. Sessionen afsluttes om $COUNT sekunder"
    let COUNT=COUNT-1
    sleep 1
  done
fi
exit

Security

Change all files to root ownership so the students cant change the script catching other students passwords etc.

chown root:root /home/ny
chown root:root /home/ny/.profile
chown root:root /home/ny/bin
chown root:root /home/ny/bin/nybruger